A silver halide color photographic material generally has a number of silver halide emulsion layers each of which is sensitive to one of the three primary colors, blue, green or red. In the material, the respective layers are colored yellow, magenta or cyan and reproduce a color image by a so-called subtractive color process.
Accordingly, the color image to be reproduced is influenced by the wavelength range to which the respective layers are sensitive (spectral sensitivity distribution) and, in addition, noticeably depends upon the yellow, magenta and cyan color hues formed in the respective layers, or upon the spectral absorption characteristics of the colored dyes in the layers. In general, the characteristics are variously limited by the raw materials used to prepare the photographic material and do not sufficiently satisfy the theoretical ideal system.
With respect to the problem of the spectral sensitivity distribution, various new sensitizing dyes have been developed to improve the spectral sensitivity distribution. In addition, it is known that even when the same sensitizing dye is used, the spectral sensitivity distribution of the photographic material can vary, depending upon the characteristics of the silver halide emulsions used as well as the condition for adsorbing the sensitizing dye to silver halides. For example, JP-A-61-103149 and JP-A-61-133941 (the term "JP-A" as used herein means an "unexamined published Japanese patent application") disclose that the addition of a sensitizing dye to a silver halide emulsion during the preparation of an emulsion results in a photographic material having excellent spectral sensitivity.
It is also known that the spectral sensitivity distribution is influenced by the dyes used in the photographic material. Such dyes are generally anti-irradiation dyes or anti-halation dyes, which are used to improve the sharpness of photographic materials. Examples of such dyes are the oxonole dyes, the azo dyes, and the anthraquinone dyes. In selecting such dyes, special attention must be taken to avoid dyes that negatively influence on the photographic properties of the photographic materials. Such dyes are known to negatively influence photographic materials, for example, by causing deterioration in the storability of raw films, by causing deterioration of the white background portion of processed films due to insufficient discoloration and dissolution of the dyes during processing, by staining the color images formed due to the retardation of the desilvering speed, by causing an acceleration of latent image fading, by lowering sensitivity, and by increasing fog.
For example, JP-A-52-20830 discloses a color photographic material containing a water-soluble bis-pyrazolonepentamethineoxonole dye having a spectral absorption maximum in the wavelength range of from 580 to 630 nm. Using this dye, the spectral sensitivity distribution of the red-sensitive layer or the green-sensitive layer in the material is improved and therefore the material has improved color reproducibility. However, this dye interferes with the spectral sensitization of the material; decreases the storability of the material; and the color of the dye often remains in the image formed after processing of the material.
JP-A-51-1419 discloses incorporation of a bis-pyrazolonemonomethineoxonole dye which has an absorption maximum in a shorter wavelength range than 440 nm. Such dye can absorb a short wavelength blue light falling within the range of from 390 to 440 nm. Also incorporation is a bispyrazolonetrimethineoxonole dye having an absorption maximum in the range of from 460 to 520 nm. The inclusion of both dyes improved the spectral sensitivity distribution of the blue-sensitive emulsion layer of the material. However, the dyes also interfere with the spectral sensitization of the material and worsen the storability of the material. In addition, the color of these dyes often remains in the image formed in the processed material.
JP-A-1-106047 discloses a positive-positive silver halide color photographic material which contains a new hydroxy/pyridoneoxonole dye and which has improved color reproducibility due to the addition of this dye. In accordance with the method, an optimum spectral sensitivity of a positive-positive silver halide material is realized, as well as the fact that the color of the dye added does not remain in the color image formed after processing. However, the quality of the processing bath, particularly the bath in which bleaching takes place, is decreased by the dye so that the desilvering of the material being processed is deteriorated and, as a result, the quality of the white background portion in the image formed also decreases. This is particularly noticeable when the positive-positive silver halide color photographic material contains a colloidal silver.
Generally, a conventional positive-positive silver halide photographic material uses a yellow colloidal silver layer as a yellow filter layer to improve color reproducibility. If there is a yellow filter layer, a blue-sensitive layer does not color in a positive-positive silver halide photographic material when exposed to blue light, then a green-sensitive layer and a red-sensitive layer are colored to magenta and cyan, respectively. On the other hand, if there is no yellow filter layer, a green-sensitive layer and a red-sensitive layer, in addition to a blue-sensitive layer, are sensitized, resulting in insufficient magenta and cyan color formation, then blue color formation becomes insufficient.
It has been known that the presence of such a colloidal silver layer tends to cause insufficient desilvering and worsen white portions. JP-A-63-159847 proposes to improve this problem.
The insufficient desilvering due to a colloidal silver is largely influenced by not only properties of the colloidal silver (size, form, distribution, etc.) but also other additives in a photographic material. The dyes which has been discussed above are an example of such an additive which influences on insufficient desilvering due to a colloidal silver.
Various additives have been studied and used for accelerating the bleaching and for preventing the insufficient desilvering of processed photographic materials. For instance, to this end a variety of compounds are known, such as various mercapto compounds as described in U.S. Pat. No. 3,893,858, British Patent 1,388,425 and JP-A-53-141623; disulfido bond-having compounds described in JP-A-53-95630; thiazolidine derivatives described in JP-B-53-9854 (the term "JP-B" as used herein means an "examined Japanese patent publication); isothiourea derivatives described in JP-A-53-94927; thiourea derivatives described in JP-B 45-8506 and JP-B-49-26586; thioamide compounds described in JP-A-49-42349; and dithiocarbamic acid salts described in JP-A-55-26506.
JP-A-63-8741 discloses an effective bleaching accelerator for positive emulsions.
But even when such a bleaching accelerator is used, there is a case where bleaching acceleration is insufficient depending on the structure of a photographic material. In the hydroxy/pyridoneoxonole dye of JP-A-1-106047 discussed above, even though such a bleaching accelerator is used, insufficient desilvering due to deterioration of a bath has not fully improved.
The followings are positive-positive silver halide color photographic materials that give a color positive image from a color positive original, for example, color reversal films, color duplicating films and color reversal papers for a reversal processing system; autopositive color films and autopositive color papers for an autopositive processing system; and instant films and diffusion transfer type dry color papers for diffusion transfer processing systems. However, in such positive-positive silver halide color photographic materials, it is difficult to plan the spectral sensitivity distribution because the color positive originals are so diverse.
The problems inherent with positive-positive silver halide color photographic materials are not solved sufficiently by any of the above described methods. In addition, originals that are to be duplicated using positive-positive silver halide photographic materials often contain white paper areas or transparent film areas. Reproducibility of the white part and the transparent part is one important characteristic of positive-positive photographic materials. Thus, dramatic improvement is possible by removing as much as of the stain caused by remaining dyes or remaining silver.
In particular, remaining silver in processed positive-positive silver halide photographic materials having an yellow-filter (YF) colloidal silver layer is frequent, and removing this is important.